Recently, the market competitiveness for both tube type and bulb type LED lighting fixtures for indoor illumination is limited due to the problems of high directivity, glare, difficulty of heat dissipation due to the close arrangement of LED lamps, heavy weight of the heat dissipation plate, and the high cost of designing. These problems are also an obstacle for the wide use of both tube and bulb LED lighting fixtures for indoor lighting. Current LED flat lamps, which are based on LCD Backlight Techniques, basically solves the problems of high directivity and glare, however still fails to consider the requirements of a Color Rendering Index, light extraction efficiency, and manufacturing cost, especially with regards to the Color Rendering Index of the eye-protection reading lamp, which can hardly meet or approximate the requirement of a standard light source (solar spectrum type).
Said LED flat lamp, based on LCD Backlight Techniques, includes a LED light strip, an aluminum frame, a Light Guide Plate and an aluminum heat conducting plate. Since the LED light strip is disposed on the aluminum profile frame, which has good heat dissipating performance, the light emitted from the LED light strip can be refracted and reflected by the Light Guide Plate to output uniform and soft light proximate to natural light. By increasing the heat dissipation area, the aluminum heat conducting plate enables heat to go through the flowing air in order to dissipate the heat completely. The Light Guide Plate is made of optical material using silk printing dots or etching dots, in order to uniformly diffuse the light emitted from the LED by refracting and reflecting in order to output the soft lighting on the whole surface.
In said LED flat lamp based on LCD Backlight Techniques, the light emitted from the LED light strip will come out from the scatterer of the silk printing dots or etching dots on the surface after multiple reflections in the Light Guide Plate. The light extraction efficiency of the LED plat lamp will decrease due to the multiple couples and reflection loss. Said aluminum profile frame and aluminum heat conduction plate will increase the manufacture cost while increasing the heat dissipation area. Furthermore, material used in said Light Guide Plate is expensive and manufacturing said Light Guide Plate will cost a lot; most importantly, when said LED plat lamp based on LCD Backlight Techniques is used for reading, the Color Rendering Index of said LED plat lamp cannot reach or approximate the requirement of a standard light source (solar spectrum type), and as a result fails to protect the eyes.